The basic principle for displaying a frame of picture by a Thin Film Transistor-Liquid Crystal Display (TFT-LCD) is as follows: a square wave with a certain width is inputted to each of pixel rows sequentially from up to down by a gate driver to strobe each of the pixel rows, and then signals required by each of pixel rows are outputted sequentially from up to down by a source driver. Recently, a display device with such structure is generally manufactured by making a gate driving circuit and a source driving circuit on a glass panel with a COF (Chip on Film) process or a COG (Chip on Glass, that is, the chip is fixed on the glass directly) process, however, when a resolution is high, outputs of both the gate driver and the source driver are more and a length of the driving circuit would increase, which is disadvantageous for a bonding process of a module driving circuit.
In order to overcome the above problem, a design of GOA (Gate Driver on Array) circuit is commonly utilized in the manufacture of existing display devices. Compared with the traditional COF or COG process, the GOA circuit not only saves the cost, but also may achieve a beautiful appearance having two symmetrical sides on the panel, meanwhile the GOA circuit removes the Bonding area and its periphery wiring space of the gate driving circuit, so that it realizes a thin frame design for the display apparatus and improves a produce capacity and a yield of the display apparatus.
In the existing design for the GOA circuit, in order to realize precise controlling to each stage of gate driving signals, it is necessary for each stage of shift register unit to comprise a plurality of functional modules, such as a pulling-up module and a pulling-down module for realizing high-low changes in potentials of gate driving signals, a control module for control a pulling-up state or a pulling-down state and an inputting module for performing a scan or reset function, and each functional module further comprises a plurality of transistors. With continual developments of the display technique, people's requirements on the display apparatus with the thin frame are increasing. The key of the display apparatus with the thin frame is how to further reduce the number of use of the transistors in the GOA circuit. In the existing design for the GOA circuit, the structure is complex because of a limitation caused by the plurality of the functional modules in the shift register unit, and thus it is difficult to further reduce the number of use of the transistors.